UNIVERSITY    OF    CALIFORNIA     AGRICULTURAL  EXPERIMENT  STATION 

BENJ.    IDE    WHEELER,    President 

COLLEGE   OF  AGRICULTURE  THOMAS  FORSYTH  HUNT    Dean  ano  D|recto„ 

H      E.    VAN    NORMAN,    Vice-Director  and   Dean 
University    Farm    School 


BERKELEY 


CIRCULAR  No.  143 

(November,  1915) 


CONTROL  OF  GRASSHOPPERS  IN 
IMPERIAL  VALLEY 

By  WALTER  E.  PACKARD 


Grasshoppers  have  caused  appreciable  damage  in  Imperial  Valley 
during  the  past  three  or  four  years  and  have  become  so  numerous  in 
some  sections  as  to  constitute  a  pest.  The  grasshoppers  are  native  to 
this  section,  being  found  in  the  mountains  surrounding  the  valley  and 
along  the  river  bottoms  where  vegetation  is  sufficient  to  maintain  them. 
Poor  cultural  conditions,  especially  in  alfalfa  fields,  have  allowed  the 
grasshoppers  to  multiply  almost  unrestricted,  which  accounts  for  their 
present  numbers. 

The  greatest  damage  has  been  done  in  alfalfa  fields,  although 
cotton,  corn,  garden  truck  and  trees  have  been  more  or  less  injured, 
in  some  cases  seriously.  Many  old  alfalfa  stands,  which  would  ordi- 
narily yield  from  three-fourths  of  a  ton  to  one  ton  and  a  half  of  hay 
per  cutting  have  been  eaten  clean,  nothing  remaining  but  bare  stems. 
Young  alfalfa  is  often  so  weakened  by  being  eaten  close  to  the  ground 
that  replanting  is  necessary.  When  the  grasshoppers  have  matured 
into  the  winged  stage  and  the  feed  becomes  scarce,  large  numbers  drift 
to  adjoining  corn  or  cotton  fields,  where  the  damage  has  been  consider- 
able. Where  the  corn  or  cotton  is  young  the  grasshoppers  almost 
destroy  the  stand.  Young  citrus  trees  seem  to  be  especially  attractive 
to  grasshoppers,  for  they  not  only  eat  the  leaves  and  part  of  the  fruit 
but  large  areas  of  bark,  girdling  the  smaller  stems  and  branches.  As 
many  as  one  hundred  to  three  hundred  grasshoppers  have  been  counted 
on  one  small  tree.  Other  varieties  of  trees  have  been  damaged,  but 
to  a  lesser  degree.  Success  with  small  gardens  has  been  almost  impos- 
sible where  the  gardens  are  situated  near  an  alfalfa  field  infested  with 
grasshoppers,  as  the  young  growth  is  eaten  off  as  soon  as  it  appears 
above  the  ground.    Large  acreages  of  beans  have  been  destroyed  when 


Fig.  1. — The  most  common  species  of  grasshopper  in  Imperial  Aralley. 
(Photo  by  Mr.  Geo.  E.  Stone) 


Fig.  2. — Alfalfa  field  illustrating  a  complete  defoliation  by  grasshoppers. 
This  crop  should  have  been  saved  by  cutting  before  serious  damage  was  done. 
The  use  of  the  grasshopper  catcher  and  poison  properly  handled  would  have 
saved  at  least  two  cuttings  in  this  case. 


the  plants  were  just  coming  up,  and  crops  have  been  ruined  by  the 
attack  of  grasshoppers  at  blossoming  time.  The  flowers  seem  to  be  a 
special  attraction  as  it  often  happens  the  flower  buds  are  the  only  parts 
injured  badly. 

There  are  several  species  of  grasshoppers  in  this  section,  the 
Melanoplus  devastator  causing  the  most  damage  on  account  of  their 
very  large  numbers.  A  very  large,  light  green  grasshopper,  Schistocerca 
vaga,  has  been  a  common  pest  on  trees,  especially  willow  trees,  for  a 
good  many  years.     The  latter  appear  in  July  in  large  numbers,  but 


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Fig.  3. — Orange  tree  completely  defoliated  by  grasshoppers.  Not  only  are 
the  leaves  eaten  but  the  bark  and  twigs,  and  many  large  branches  were  de- 
stroyed and  the  trees  seriously  set  back.  This  orchard  was  grown  on  unculti- 
vated land  and  adjoins  an  alfalfa  field  infested  with  grasshoppers.  This  damage 
could  have  been  avoided  easily. 


so  far  have  not  been  noticed  on  plants  of  economic  value.  None  of 
the  species  found  in  the  valley  are  truly  migrating,  although  after 
reaching  the  winged  stage  they  drift  from  one  field  to  another  as  the 
food  becomes  scarce.  This  is  very  noticeable  in  alfalfa  fields  after  the 
alfalfa  has  been  eaten  down.  During  a  wind  the  grasshoppers  often 
appear  to  be  migrating,  as  they  fly  quite  a  distance  before  alighting, 
but  there  is  no  true  migration  as  occurs  in  many  other  sections. 

The  life  histories  of  the  various  species  of  grasshoppers  have  not 
been  worked  out  under  local  conditions  and  therefore  the  exact  habits 
of  the  insects  are  not  known.  It  is  known,  however,  that  the  hoppers 
lay  their  eggs  during  the  fall,  from  the  last  of  August  on.  The  eggs 
are  laid  from  one-half  inch  to  an  inch  in  depth.     A  few  grasshoppers 


live  over  during  the  winter  time,  although  most  of  them  disappear 
gradually  during  the  fall  and  are  almost  gone  by  the  middle  or  last 
of  November.  The  young  hoppers  appear  first  in  April  in  large 
numbers,  although  they  are  often  not  noticed  until  May,  when  they 
become  large  enough  to  do  considerable  damage.  The  young  hoppers 
attain  the  winged  stage  quite  early — in  four  or  five  weeks  after  hatch- 
ing. Although  it  is  not  known  that  more  than  one  generation  of  a 
single  species  occurs  in  this  section,  it  has  been  noted  that  the  hoppers 
of  the  first  brood  lay  eggs  in  May  and  a  second  brood  appears  in  much 
greater  numbers  than  the  first  during  the  first  part  of  July.  In 
some  cases  a  third  brood  has  been  noted  in  September.  It  is  possible 
that  this  is  either  a  case  of  two  or  three  generations  in  a  year,  or  it  is 
possible  that  it  is  a  case  of  a  later  hatching  of  eggs.  The  specific  facts 
regarding  the  life  histories  of  the  grasshoppers  are  of  more  scientific 
interest  than  of  economic  value  since  the  same  methods  must  be  used 
in  the  control  of  the  insect  in  one  case  as  in  another. 

The  control  of  the  grasshopper  should  not  prove  a  difficult  problem 
in  Imperial  Valley,  since  local  conditions  are  very  favorable  for  their 
control  if  concerted  action  is  taken  by  the  property  owners.  Practi- 
cally all  of  the  grasshoppers  now  present  are  hatched  within  the 
irrigated  area  as  has  been  noted,  as  the  native  desert  does  not  afford 
a  favorable  breeding  ground.  It  is  not  necessary  as  in  most  sections, 
therefore,  to  attempt  to  control  a  vast  breeding  ground,  or  to  combat 
a  hoard  appearing  in  the  sky  from  some  distant  place.  As  it  happens, 
the  most  effective  control  measure  is  cultural  treatment,  which  is  in 
line  with  good  farming  so  that  the  labor  of  exterminating  the  grass- 
hoppers is  not  an  economic  loss,  but  will  rather  tend  to  improve 
cultural  conditions.  In  this  section  where  nature  is  so  bountiful,  it  is 
easy  to  fall  into  the  habit  of  doing  as  little  cultivation  as  possible,  even 
though  a  reasonable  amount  of  cultivation  gives  profitable  results. 
Concerted  action,  however,  is  absolutely  essential  to  complete  success, 
as  the  work  of  one  man  is  almost  a  loss  if  his  neighbors  do  not  also 
fight  this  pest.  The  neighborhood  interest  should  be  stimulated  so 
that  every  man  will  see  that  his  part  is  carried  out. 

As  has  been  stated,  cultural  treatment  is  the  most  successful  way 
of  handling  the  grasshoppers.  Thorough  discing,  or  preferably  plow- 
ing where  feasible,  will  destroy  a  very  large  percentage  of  the  eggs 
as  they  are  turned  up  and  exposed  to  the  weather.  This  cultivation 
should  be  carried  on  during  December  Or  January  and  in  June,  after 
the  eggs  have  been  laid  and  before  they  hatch.  The  effectiveness  of 
this  treatment  can  be  very  clearly  seen  in  any  part  of  the  valley,  as 


the  hoppers  almost  invariably  appear  in  uncultivated  alfalfa  fields, 
along  ditch-banks  or  other  uncultivated  places.  The  hoppers  never 
appear  in  corn  or  cotton  fields  which  have  been  cultivated,  but  migrate 
to  these  fields  from  adjoining  alfalfa  fields  where  cultivation  has  not 
been  practiced.  The  difference  between  the  cultivated  and  the  un- 
cultivated alfalfa  field  is  very  noticeable.  It  is  probable  that  a 
thorough  discing  of  the  alfalfa  fields  during  June  will  destroy  a  large 
percentage  of  the  eggs  which  will  hatch  the  last  of  June  or  the  first 
of  July. 

The  discing  to  be  effective  must  be  very  thorough,  as  practically 
all  of  the  land  must  be  disturbed.  Simply  running  the  disc  or  alfalfa 
cultivator  through  the  field  once  will  not  accomplish  the  results,  for 
the  land  between  each  disc  blade  forms  an  undisturbed  ridge  where 
the  eggs  can  develop  normally.  The  land  should  be  covered  two  or 
three  times  by  overlapping  from  a  half  to  two-thirds  each  round.  In 
order  to  stir  the  ground  without  injuring  the  stand  of  alfalfa,  the 
disc  should  be  sharp  and  heavily  weighted,  with  the  disc  set  almost 
straight.  Cross-discing  is  advisable  when  possible  without  too  great 
injury  to  the  borders. 

If  the  cultural  treatment  has  been  neglected  or  for  any  reason 
has  not  proved  effective,  the  grasshoppers  which  appear  in  the  fields 
can  be  easily  caught  by  some  form  of  hopper-dozer.  Several  devices 
have  been  tried  in  the  valley  and  where  properly  used  have  proved  to 
be  very  efficient  and  economical.  In  many  cases  from  fifty  to  seventy- 
five  per  cent  of  the  hoppers  have  been  caught  in  going  over  the  field 
once  with  the  hopper-dozer.  The  destruction  of  so  large  a  percentage 
will  be  sufficient  to  prevent  any  serious  loss  to  crops,  although  in 
most  cases  it  will  be  best  to  go  over  the  fields,  two,  three,  or  four  times 
in  order  to  reduce  the  numbers  to  a  minimum.  A  catch  of  thirteen 
gallons  of  mature  grasshoppers  will  remove  one  hopper  from  every 
square  foot  of  space  on  an  acre.  Such  a  catch  can  be  secured  in  fifteen 
to  twenty  minutes'  work  in  a  badly  infested  field.  It  is  very  notice- 
able in  alfalfa  fields  that  the  hoppers  are  in  greater  numbers  in 
certain  patches  than  in  others.  When  the  hoppers  are  young  these 
patches  can  be  worked  over  thoroughly  with  the  hopper-dozer  and  a 
large  percentage  of  the  hoppers  caught  before  they  spread  out  over 
the  fields  and  make  the  work  more  difficult.  The  hopper-dozer  should 
be  used  early  in  the  morning  or  in  the  evening,  as  the  grasshoppers 
are  apt  to  become  too  active  during  the  middle  of  the  day.  The  work 
is  often  fifty  per  cent  more  effective  if  done  at  the  right  time.  Several 
farmers  who  have  tried  the  hopper-dozer  have  become  discouraged 


Fig.  4. — Catcher  used  effectively  where  grasshoppers  are  active. 
(Photo  by  Mr.  Geo.  E.  Stone) 


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Fig.  5. — Old  type  crude  oil  hopper-dozer.  The  wings  used  on  the  sides  are 
an  effective  aid  in  preventing  the  grasshoppers  from  escaping  the  hopper-dozer. 
These  wings  should  be  used  in  the  case  of  the  hopper  catcher  shown  in  figure  6. 


because  of  ineffective  results.  In  nearly  every  case  this  is  due  to  a 
neglect  of  some  of  the  fundamental  principles  necessary  to  success. 
Either  the  hopper-dozer  is  not  well  constructed  or  the  work  is  not 
done  at  the  right  times.  Often  the  first  attempts  are  unsuccessful, 
but  by  studying  the  local  conditions  the  practice  can  be  so  perfected 
that  results  will  be  secured.  No  one  should  become  discouraged  over 
an  unsuccessful  beginning,  as  it  often  happens  that  the  first  attempts 
are  not  as  successful  as  anticipated.  Repeated  trials  will  reveal  the 
defects  in  the  apparatus  or  mistakes  in  practice  so  that  further 
attempts  will  be  successful. 


Fig.  6. — A  hopper  catcher  which  has  been  used  very  successfully  in  grass- 
hopper control  work  in  Imperial  Valley.  This  is  the  most  satisfactory  device  so 
far  used  in  this  locality.     This  device  is  shown  in  the  accompanying  drawing. 


The  hopper-catcher  illustrated  in  the  accompanying  drawing  has 
proved  to  be  the  most  effective  device  so  far  used.  This  machine  is 
dragged  through  the  fields  by  two  horses,  one  at  each  end.  The  grass- 
hoppers hit  the  galvanized  front  and  slide  into  the  trap,  where  they 
are  later  killed  by  the  use  of  hot  water  and  can  be  removed  and  dried 
and  used  for  chicken  feed.  Large  quantities  of  grasshoppers  can  thus 
be  caught  and  considerable  chicken  feed  secured  where  the  grass- 
hoppers are  numerous  enough  to  do  damage  in  the  fields. 

The  old-fashioned  hopper-catcher,  in  which  a  galvanized  iron  pan 
is  filled  with  crude  oil  or  water  covered  with  kerosene,  has  been  used 
by  a  number  of  farmers  in  the  valley  with  more  or  less  success.  This 
device  is  a  simple  one  and  can  be  constructed  at  an  expense  of  from 
five  to  ten  dollars,  depending  on  the  size.     The  galvanized  iron  pan 


8 


is  from  three  to  four  feet  wide  and  from  twelve  to  sixteen  feet  long 
and  is  built  with  a  rather  high  back  so  that  the  hoppers  cannot  fly 
over.  It  is  drawn  over  the  field  in  the  same  way  as  the  hopper-catcher. 
A  small  hopper-dozer  can  be  used  in  vineyards  satisfactorily.  The 
hopper-dozer  is  drawn  between  the  rows  of  vines  with  one  horse,  and 
the  hoppers  driven  from  the  vines  by  two  men,  one  on  each  side.  Sticks 
with  white  cloth  attached  are  effective  in  driving  hoppers.  AVhen 
caught  in  crude  oil  the  grasshoppers  cannot  be  used  as  chicken  feed. 
This,  together  with  the  trouble  of  handling  the  crude  oil,  gives  the 


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Fig.  7. — Diagram  of  Hopper  Catcher,  showing  side,  front  and  top  views. 
Hoppers  are  killed  by  hot  water  poured  through  screen  into  bottom  pan.  The 
tin  vibrator  or  toe  is  an  extension  of  the  bottom  pan  and  must  be  adjusted 
properly  for  efficient  use.  (Modified  from  plans  given  in  Bull.  138  Utah  Agr. 
College.) 


hopper-catcher  described  first  the  advantage.  It  must  be  admitted 
that  this  device  has  proven  quite  efficient  in  catching  the  hoppers, 
although  the  hopper-catcher  should  do  better  work. 

The  balloon  catcher  described  in  the  accompanying  illustration  has 
been  used  successfully.  It  is  the  cheapest  device  for  catching  grass- 
hoppers, but  requires  more  labor  in  its  use.  It  is  pulled  by  two  horses 
at  a  sufficiently  rapid  speed  to  inflate  the  balloon.  The  chief  advantage 
of  this  device  is  that  it  can  be  drawn  fast  enough  so  that  it  will  catch 
a  great  many  of  the  hoppers  that  will  fly  over  the  other  catchers. 


The  hoppers  are  imprisoned  in  the  sack  at  the  apex  of  the  balloon 
and  can  be  killed  by  submerging  the  sack  in  hot  water.  They  can  be 
dried  and  used  for  chicken  feed  as  in  the  case  of  the  hopper-catcher. 
This  device  has  proved  better  for  hoppers  after  they  have  attained 
the  winged  stage  than  for  the  young  hoppers. 

After  the  field  has  been  thoroughly  covered  with  the  hopper- 
catcher,  arsenic  poison  can  be  put  out  and  a  large  proportion  of  the 
remaining  hoppers  killed.  The  mixture  most  commonly  used  is  as 
follows :  bran,  25  pounds ;  arsenic,  1  pound ;  molasses,  2  quarts  in  4 
gallons  of  water;  and  6  lemons.  The  arsenic  is  generally  in  the  form 
of  Paris  green,  which  can  be  mixed  with  a  quart  or  two  of  water. 
This  is  poured  into  a  tub  of  water  and  mixed  with  molasses,  and  the 
mixture  thoroughly  stirred.  This  can  be  added  slowly  to  the  bran  as 
water  is  added  to  mortar.  It  should  be  constantly  stirred  with  a  hoe 
so  that  the  poison  is  thoroughly  distributed  through  the  mass.  If  the 
water  containing  poison  is  simply  poured  on  to  the  bran,  the  poison 
is  not  evenly  distributed.  This  amount  of  mixture  can  be  distributed 
over  four  or  five  acres  of  ground  with  no  danger  of  killing  poultry 
or  stock,  and  will  effectively  kill  a  very  large  number  of  grasshoppers. 
If  the  poison  is  distributed  along  the  borders,  especially  immediately 
after  cutting  the  alfalfa  and  irrigating  the  field,  the  work  will  be 
most  effective.  This  poison  can  be  used  in  alfalfa,  cotton  or  corn  or 
bean  fields  where  the  grasshoppers  have  become  numerous  by  spread- 
ing with  an  ordinary  broadcast  seeder.  The  dead  grasshoppers  are 
not  noticed  for  three  or  four  days,  as  the  poison  is  slow  in  action,  but 
the  mixture  recommended  is  very  effective.  When  used  in  cotton 
fields  where  the  grasshoppers  have  been  causing  considerable  loss,  as 
many  as  fifty  to  two  hundred  grasshoppers  have  been  counted  under 
one  cotton  plant  three  or  four  days  after  the  poison  was  distributed. 
This  poison  has  been  distributed  in  the  fields  where  chickens  have  been 
feeding  and  no  loss  has  resulted.  About  one-fifteenth  of  an  ounce  of 
this  mixture  has  been  fed  to  chickens  without  serious  results. 

In  the  case  of  orchards  where  young  trees,  especially  citrus  trees, 
are  attacked  by  grasshoppers,  the  trees  can  be  completely  covered  with 
cheesecloth  which  can  be  purchased  at  from  two  and  one-half  to  three 
cents  per  yard.  This  is  economical  and  effective,  although  the  trees 
must  be  watched  carefully  and  the  cloth  removed  before  the  leaves 
begin  to  brown,  as  complete  defoliation  is  apt  to  follow  too  long  a 
covering.  Poison  can  be  distributed  around  the  base  of  the  tree  or  if 
not  too  damp,  can  be  put  in  the  branches.  This  poisoning  has  been 
done  in  a  number  of  cases  and  has  proved  very  effective.     Cheesecloth 


10 


has  also  been  used  very  satisfactorily  in  protecting  garden  truck  from 
grasshoppers.  The  cheesecloth  is  cheap,  so  that  it  is  practicable  to 
cover  the  ordinary  garden.  Small  wire  pins  made  out  of  old  bailing 
wire  can  be  used  in  tacking  the  edges  down.    In  some  cases  the  cheese- 


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Fig.  8. — Canvas  Balloon  Grasshopper  Catcher 
Sew  strips  of  canvas  together  to  make  sack  of  the  size  desired.  Cut  this 
into  three  triangles,  following  dotted  lines  given  in  the  diagram.  Sew  the  two 
distant  triangles  together  for  the  top,  using  the  center  triangular  piece  for  the 
bottom.  Cut  another  piece  of  canvas  16  x  4  diagonally  from  corner  to  corner  to  make 
the  two  side  pieces,  leaving  extensions  at  each  end  as  aprons.  A  2x3  is  fastened 
to  the  bottom  and  rope  extended  from  both  bottom  and  top  of  the  canvas  as  in 
Figure  3.  A  hook  is  fastened  to  the  apex  of  the  balloon,  to  which  a  common 
gunny  sack  can  be  attached  for  catching  grasshoppers.  The  canvas  apron  is 
fastened  underneath  the  sack  to  prevent  it  from  wearing  out. 

Cost  Data 

21  yds.  36-in.  10-oz.  duck  at  17%c $3.65 

Sew  canvas  2.00 

2y2  lbs.  %6-in,  rope  at  20c 50 

One  2x3—10  piece  of  lumber  20 

$6.35 


cloth  can  be  torn  in  half  so  that  one  width  will  cover  two  rows.  It 
should  not  be  left  too  long,  however,  but  removed  as  soon  as  the  plants 
appear  to  be  pushing  it  up.  For  lettuce  this  method  seems  to  be 
especially  favorable  as  it  produces  a  very  tender  plant.  It  has  been 
used  on  commercial  market  gardens  profitabty,  so  that  the  price  is 


11 

not  prohibitive.  Poison  can  be  used  in  the  gardens,  but  it  is  more 
apt  to  be  dangerous  to  chickens  or  to  children  there  than  in  the  field 
and  is  therefore  not  generally  recommended. 

It  has  been  observed  that  when  sheep  have  pastured  on  land  during 
the  winter,  very  few  grasshoppers  appear  in  the  spring.  This  is 
apparently  due  to  the  trampling  of  the  ground  by  the  small  sharp 
hoofs.  Turkeys  and  chickens  have  of  course  been  used  effectively  on 
limited  areas,  but  could  not  be  used  as  a  general  remedy  for  this  pest 
for  apparent  economic  reasons. 

Other  methods  suggested  by  farmers,  such  as  smudging,  burning 
and  driving,  are  not  adapted  to  local  conditions,  since  they  are  less 
effective  than  in  other  localities  where  conditions  are  different. 

If  the  recommendations  given  above  are  followed  out  and  concerted 
action  is  taken,  there  is  no  doubt  but  that  the  grasshopper  troubles 
of  Imperial  Valley  can  be  very  easily  controlled.  It  is  strongly  urged 
that  the  farmers  and  the  communities  where  the  grasshoppers  have 
caused  loss  get  together  in  a  co-operative  arrangement  to  carry  out 
the  methods  above  described.  One  hopper-catcher  will  serve  quite  a 
large  area,  so  that  the  expense  if  distributed  is  very  small  indeed.  One 
man  could  be  given  the  work  of  using  the  hopper-catcher  in  a  com- 
munity and  could  go  from  one  place  to  another,  so  he  would  become 
especially  proficient  and  the  results  of  his  work  would  be  satisfactory. 


STATION  PUBLICATIONS  AVAILABLE  FOR  DISTRIBUTION 


REPORTS 
Adaptation,   and  Grafting. 


Appendix  to   Viticultural 


1897.      Resistant  Vines,  their  Selection, 
Report  for   1896. 

1902.  Report  of  the  Agricultural  Experiment   Station   for   1898-1901. 

1903.  Report  of  the  Agricultural  Experiment   Station   for   1901-03. 

1904.  Twenty-second  Report  of  the  Agricultural  Experiment   Station   for   1903—04. 

1914.  Report  of  the   College  of  Agriculture  and  the   Agricultural   Experiment   Statoin,   July, 

1913-June,  1914. 

1915.  Report  of  the  College  of  Agriculture  and  the   Agricultural   Experiment   Station,   July, 

1914-June,  1915. 

BULLETINS 


No. 

168. 

169. 
170. 
174. 
177. 

178. 
184. 

185. 

195. 
197. 


198. 
203. 

207. 
208. 
211. 

212. 
213. 
216. 


Observations    on    Some    Vine    Diseases 

in  Sonoma  County. 
Tolerance  of  the  Sugar  Beet  for  Alkali. 
Studies  in  Grasshopper  Control. 
A  New  Wine-Cooling  Machine. 
A   New    Method    of    Making    Dry    Red 

Wine. 
Mosquito   Control. 
Report    of    the    Plant    Pathologist    to 

July  1,    1909. 
Report  of  Progress  in   Cereal   Investi- 
gations. 
The  California  Grape  Root-worm. 
Grape  Culture  in  California ;  Improved 

Methods      of     Wine-making;      Yeast 

from   California    Grapes. 
The  Grape  Leaf-Hopper. 
Report    of    the    Plant    Pathologist    to 

July   1,    1906. 
The  Control  of  the  Argentine  Ant. 
The  Late  Blight  of  Celery. 
How  to   Increase  the   Yield  of  Wheat 

in   California. 
California   White   Wheats. 
The  Principles  of  Wine-making. 
A     Progress     Report     upon     Soil    and 

Climatic     Factors      Influencing     the 

Composition  of  Wheat. 


No. 

220.   Dosage  Tables. 

225.   Tolerance  of   Eucalyptus  for  Alkali. 

227.   Gratfe  Vinegar. 

230.   Enological    Investigations. 

234.   Red  Spiders  and  Mites  of  Citrus  Trees. 

241.  Vine  Pruning  in  California.      Part  L 

242.  Humus  in  California  Soils. 
244.   Utilization  of  Waste  Oranges. 

246.   Vine  Pruning  in  California.     Part  II. 

248.  The  Economic  Value  of  Pacific  Coast 

Kelps. 

249.  Stock  Poisoning  Plants  of  California. 

250.  The  Loquat. 

251.  Utilization    of    the    Nitrogen    and    Or- 

ganic  Matter   in    Septic    and    Imhoff 
Tank  Sludges. 

252.  Deterioration  of  Lumber. 

253.  Irrigation   and   Soil   Conditions   in   the 

Sierra  Nevada  Foothills,  California. 

254.  The  Avocado  in  California. 

255.  The    Citricola    Scale. 

256.  Value  of  Barley  for  Cows  fed  Alfalfa. 

257.  New  Dosage  Tables  . 

258.  Mealy  Bugs  of  Citrus  Trees. 

259.  Commercial  Fertilizers. 

260.  Availability     Studies     on     Nitrogenous 

Fertilizers. 


No. 
65.   The  California   Insecticide  Law. 

69.  The    Extermination    of    Morning-Glory. 

70.  Observations    on    the    Status    of    Corn 

Growing  in  California. 
76.   Hot  Room  Callusing. 

79.  List  of  Insecticide  Dealers. 

80.  Boys'  and  Girls'  Clubs. 

82.  The     Common     Ground     Squirrels     of 

California. 

83.  Potato  Growing  Clubs. 
87.   Alfalfa. 

100.  Pruning  Frosted  Citrus  Trees. 

101.  Codling    Moth    Control    in    the    Sacra- 

mento Valley. 

106.  Directions  for  using  Anti-Hog-Cholera 

Serum. 

107.  Spraying  Walnut  Trees  for  Blight  and 

Aphis  Control. 

108.  Grape  Juice. 

109.  Community  or   Local   Extension   Work 

by  the  High  School  Agricultural  De- 
partment. 

110.  Green  Manuring  in  California. 

111.  The  Use  of  Lime  and  Gypsum  on  Cali- 

fornia Soils. 

113.  Correspondence  Courses  in  Agriculture. 

114.  Increasing  the  Duty  of  Water. 

115.  Grafting  Vinifera  Vineyards. 

117.   The    Selec'ion    and    Cost    of    a    Small 
Pumping   Plant. 


CIRCULARS 

No. 

118. 
119. 
121. 


The  County  Farm  Bureau 

Winery  Directions. 

Some    Things    the    Prospective    Settler 

Should  Know. 
122.  The  Management  of   Strawberry   Soils 

in  Pajaro  Valley. 

124.  Alfalfa  Silage  for  Fattening  Steers. 

125.  Aphids  on  Grain  and  Cantaloupes. 

126.  Spraying  for  the  Grape  Leaf  Hopper. 

127.  House  Fumigation. 

128.  Insecticide   Formulas. 

129.  The  Control  of  Citrus  Insects. 

130.  Cabbage   Growing   in    California. 

131.  Spraying  for  Control  of  Walnut  Aphis 

132.  When      to      Vaccinate      against      Hog 

Cholera. 

133.  Country  Farm  Advisor. 

134.  Control  of  Raisin  Insects. 

135.  Official   Tests   of   Dairy   Cows. 

136.  Melilotus    Indica. 

137.  Wood  Decay  in   Orchard  Trees. 

138.  The  Silo  in   California  Agriculture. 

139.  The    Generation    of    Hvdrocvanic    Acid 

Gas  in  Fumigation  by   Portable   Ma- 
chines. 

140.  The  Practical  Application  of  Improved 

Methods  of   Fermentation   in   Califor- 
nia Wineries  during  1913  and  1914. 

141.  Standard    Insecticides    and    Fungicides 

versus    Secret    Preparations. 

142.  Practical  and  Inexpensive  Poultry  Ap- 

pliances. 


